I have two measures, the first scale was validated succesfully. Now, I want to validate the second measure by using concurrent validity. However, the first measure has the sample size of 300; on the other hand the second measure has the sample size of just 97. I have run across something which is about Bayesian calculation for equalize the sample size of different populations, but I am not sure how and what can be done for such situation. Is there any method (bootstrapping, cross validation techniques?) eliminating this problem before construct concurrent validity?
Thank you very much